1. Field of the Invention
This invention relates, generally, to bailers. More particularly, it relates to a bailer having a construction that controls and slows the rate of descent of the bailer into a liquid fluid to a speed sufficiently slow to substantially avoid agitation of the liquid fluid from which a sample is being taken.
2. Description of the Prior Art
One of the problems confronting the bailer industry is the speed with which samples are normally taken. The people in the field who take samples from wells or other bodies of liquid are generally interested in taking as many samples per day as possible. Accordingly, many developments in the industry have been designed to increase the speed of bailer insertion into a well. For example, there are a number of bailer designs that add weights to a bailer to increase its insertion speed. Unfortunately, this also increases the agitation of the liquid.
Moreover, various environmental protection agencies at the state level are reporting an unacceptably high rate of bad sample data attributed largely to the speed of sample collection. Apparently, a fast-traveling bailer increases agitation and causes turbidity by stirring up sediment and the like that would remain undisturbed if the bailer were entering into and traveling through the liquid fluid at a slower rate. Thus, pollutants are collected that would not have been collected if the bailer had descended and filled at a slower rate. Agitation can also increase the oxygen content of the liquid, thereby generating false data.
There are two relatively obvious solutions to the problem. The first solution, not favored by state agencies, is to provide better training to those who work with bailers in the field so that they will collect the samples at a slower rate. The time and expense that would be required to educate such workers is thought to be prohibitive. Nor do such agencies trust the efficacy of such training.
The second solution, favored by some experts in the field and some governmental authorities, is to ban the use of bailers and to mandate that pumps be employed to collect samples. There are several problems with that solution. Most importantly, perhaps, is the fact that pumps have moving parts capable of stirring up sediment and their use will therefore not solve the agitation and turbidity problems. Moreover, pumps are much more expensive than bailers. A disposable bailer may cost no more than a few dollars but a pumping system can cost from fifteen hundred dollars to triple that amount. It follows that pumps of such expense cannot be used one time and discarded as are bailers. Instead, to avoid cross-contamination between various wells, a pumping system must be thoroughly cleaned after each use. This consumes large quantities of pure water and time.
It has also been proposed that to avoid the cross contamination problem and the time and expense of cleaning a pump after each use, a pump could be permanently installed at each sample collection site, such as a well. This solution is impractical in view of the extremely large number of collection sites. For example, there may be a hundred wells just in one small area near a known source of contamination.
Moreover, pumps require electrical power which is often unavailable in remote collection sites. A portable generator would have to be brought to such locations, thereby driving up the cost of sample collection even higher.
Pumps, then, are clearly not the answer to the problem.
In view of the prior art, considered as a whole, at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent arts how the problems associated with poor samples based upon excessive bailer speed insertion could be resolved.
The longstanding but heretofore unfulfilled need for a bailer that descends slowly into a body of liquid and which fills slowly to reduce agitation is now met by a new, useful, and nonobvious invention. The novel bailer includes an elongate, tubular main body having a hollow interior and having an open upper end. A plug closes said upper end and a small perforation of predetermined size is formed in the plug. A check ball and a check ball seat are disposed at a lower end of the bailer and the check ball lifts from the check ball seat when the bailer is lowered into a body of liquid fluid, in response to an inflow of liquid fluid into the elongate, tubular main body. In this way, air positioned below the plug and above the liquid fluid is constrained to flow out of the elongate, tubular main body through the perforation as liquid fluid flows into the elongate, tubular main body. Accordingly, a back pressure is created by the air because the air cannot flow through the perforation at a rate of flow that exceeds the rate of flow of the liquid fluid into the elongate, tubular main body. Thus, the bailer descends slowly into the liquid fluid and the liquid fluid flows slowly into the elongate, tubular main body and agitation of the liquid fluid is reduced.
When the bailer is being emptied, the presence of the plug and the small perforation creates a near vacuum in the space below the plug and above the liquid level because ambient air cannot flow through the perforation into the space as quickly as the liquid fluid can flow from the bailer. This near vacuum thus provides a braking action that prevents rapid outflow of the liquid sample, again reducing agitation.
In a first embodiment, the perforation is formed in the plug and in a boss means that projects upwardly therefrom. The perforation is perhaps more accurately described as a throughbore in that it extends through the boss means and the plug. In a second embodiment, the boss means is eliminated and the throughbore is formed in the plug only.
In a third embodiment, one or more flat baffle walls are mounted to the external wall of the elongate, tubular main body to slow the rate of descent of the bailer. The plug and the perforation formed therein may be eliminated so that the elongate, main tubular body is open at its uppermost end or the plug and perforation formed therein may be maintained and used in conjunction with the baffle wall.
In a fourth embodiment, the baffle wall defines a downwardly opening cavity.
A fifth embodiment includes a stabilizer means in the form of a hollow tube that is secured to the lowermost end of the bailer in leading relation thereto.
A primary object of the invention is to provide a bailer that descends slowly into a body of liquid fluid to reduce agitation and turbidity.
A closely related object is to provide such a bailer that does not require training or educating workers in the field as to their proper use.
Another object is to provide a bailer which may also be emptied slowly.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.